Terrin Westfall is the younger brother of Chaol Westfall and (because Chaol abdicated his title) the heir of the Adarlanian duchy of Anielle.


Lord Westfall describes Terrin as "all gangly limbs and awkward angles" due to genetics from Terrin's mother.


As Terrin never physically appears in the novels, little is known about his personality. His father, Lord Westfall, believes that he is weak and unfit to rule Anielle, claiming he is a scholar and not a warrior.